AP Statistics Chapter 2 Test



AP Statistics Chapter 11/12 Review Name:____________________

1. A significance test gives you a P-value of .04. From this we can

(a) Reject [pic] at 1% significance level

(b) Reject [pic] at 5% significance level

(c) Say that the probability that [pic] is false is .04

(d) Say that the probability that [pic] is true is .04

(e) Say the results are significant at the 1% level

2. A significance test was performed to test the null hypothesis [pic]vs the alternative hypothesis

[pic]. The test statistic is z = 1.40. The P-value for this test is approximately

(a) .16 (b) .08 (c) .003 (d) .92 (e) .70 (f) None of the above

3. Which of the following are true statements?

I. Tests of significance are designed to measure the strength of evidence against the null hypothesis

II. A well-planned test of significance should result in a statement either that the null hypothesis is true or

that it is false.

III. The alternative hypothesis is one-sided if there is interest in deviations from the null hypothesis in only

one direction

(a) I and II (b) I and III (c) II and III (d) I, II and III

(e) None of the above gives the complete set of true responses

4. An automotive company executive claims that a mean of 48.3 cars per dealership are being sold each month. A major stockholder believes this claim is high and runs a test by sampling 30 dealerships. What conclusion is reached if the sample mean is 45.4 cars with a standard deviation of 15.4?

(a) There is sufficient evidence to prove the executive’s claim true

(b) There is sufficient evidence to prove the executive’s claim false

(c) The stockholder has sufficient evidence to reject the executive’s claim

(d) The stockholder does not have sufficient evidence to reject the executive’s claim

(e) There is not sufficient evidence to reach any conclusion

5. A city spokesperson claims that the mean response time for arrival of a fire truck at a fire is 12 minutes. A newspaper reporter suspects that the response time is actually longer and runs a test by examining the records of 64 fire emergency situations. What conclusion is reached if the sample mean is 13.1 minutes with a standard deviation of 6 minutes?

(a) The P-value is less than .001, indicating very strong evidence against the 12 minute claim

(b) The P-value is .01, indicating strong evidence against the 12 minute claim

(c) The P-value is .07, indicating some evidence against the 12 minute claim

(d) The P-value is .08 indicating very little evidence against the 12 minute claim

(e) The P-value is .43, indicating no evidence against the 12 minute claim

6 . An IRS representative claims that the average deduction for medical care is $1250. A taxpayer who believes that the real figure is lower samples 12 families and comes up with a mean of $934 and a standard deviation of $616. Where is the P-value?

(a) Below .01 (b) Between .01 and .025 (c) Between .025 and .05 (d) Between .05 and .10 (e) Over .10

7. If t = -3.56 for a two sided t-test where the same size was 20, where would the P-value lie?

(a) Below .0005 (b) Between .0005 and .001 (c) Between .001 and .0025

(d) Between .002 and .005 (e) Cannot be determined without more information

8. If z = 1.89 for a one-sided z-test, what would the P-value be?

(a) .029 (b) .0588 (c) .485 (d) .9706 (e) Cannot be determined, the sample size is needed

9. Which of the following statements are true?

I. One should examine your data before deciding whether to use a one-sided or two-sided hypothesis test

II. If the P-value is .05, the probability that the null hypothesis is correct is .05

III. The larger the P-value, the more evidence there is against the null hypothesis

(a) I only (b) II only (c) III only

(d) II and III (e) None of the above gives the complete set of true responses

10. Which of the following are correct?

I. The power of a significance test depends on the alternative value of the parameter

II. The probability of a type II error is equal to the significance level of the test

III. Type I and type II errors only make sense when a significance level is chosen in advance

(a) I and II only (b) I and III only

(c) II and III only (d) I, II and II (e) None of the above gives the complete set of true responses

11. Which of the following best describes the power of a test?

(a) It’s the probability that you mistakenly accept a false hypothesis

(b) It’s the probability that you correctly accept a true hypothesis

(c) It’s the probability that you mistakenly reject a true hypothesis

(d) It’s the probability that a test will successfully reject a false hypothesis

(e) None of the above

12. The P-value tells you:

(a) The probability that your results are statistically significant

(b) The probability that your sample mean is equal to the population mean

(c) The probability that you’d get results as extreme as you did, from random variation alone

(d) The probability that [pic]is true

(e) The significance level

13. If a two sided hypothesis was significant at the 5 % level, would a one sided test with the same test statistic also be significant at the 5% level? Explain

14. A steel mill’s milling machine produces steel rods that are supposed to be 5cm in diameter. When the machine is in statistical control, the rod diameters vary according to a normal distribution with a mean [pic]= 5cm. A large sample of 150 produced by the machine yields a sample mean diameter of 5.005cm and a stand. Dev. of 0.02 cm.

a) Conduct a significance test([pic]) to test the claim that the rods are 5cm on average.

b) Interpret the p-value you found in part a) in the context of this question

c) What can you say about the 99% confidence interval for the steel rods based on your results in part a)?

15. Mars Inc., maker of M&M candies, claims that they produce M&Ms with the following distribution:

Brown: 30% Red: 20% Yellow: 20% Orange 10% Green: 10% Blue: 10%

A bag of M&Ms was randomly selected from the grocery store shelf, and the color counts were as follows:

Brown: 16 Red: 11 Yellow: 19 Orange: 5 Green: 7 Blue: 3

You want to conduct an appropriate test of the manufacturer’s claim for the proportion of yellow M&Ms.

a) Assuming that this bag of candies is a random sample of all M&Ms produced, conduct an appropriate

test of hypotheses for mar’s published distribution of yellow M&M’s

b) Based on this sample, calculate a 90% confidence interval for the proportion of yellow M&M candies produced by Mars.

c) Explain how parts a) and b) are connected.

d) What would you change in this experiment to obtain more reliable results?

16. An accounting firm measures the blood pressures of 10 of its certified public accountants (CPA’s) before and during the spring 1996 tax season. The systolic blood pressure for the 10 individuals, designated as A through J were as follows:

|A |B |C |D |E |F |G |H |I |J | |Before |110 |124 |98 |105 |115 |120 |118 |110 |123 |95 | |During |115 |126 |97 |108 |115 |124 |119 |113 |121 |96 | |Is there sufficient evidence that blood pressure rises during tax season? Perform the appropriate test and state your conclusions

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download